I created a banner ad and assigned it a zone. I also have some sidebar ads that have also been assigned a different zone. But now when I place my banner ad on the top of my page it also creates a second image and places it in an unassigned zone.
I have gone back and checked all of my zones and they are correct (no conflicts) and made sure the correct zone assignment was checked in the actual ad and it was.
Can you please advise.
If you don't specify a Zone on one of your ad tags, Zones won't be factored into the ad selection/query for the tag. That means that all ads can appear in that ad tag.
To explain a bit more in depth, if you specify a zone (say 'myzone') on your tag/widget, the query will include "show ads where the ad is targeted to 'myzone'". If the tag/widget doesn't have a zone specified, that part of the query is left off and what zones are targeted insn't factored into the ad query/selection.
Most people either use Zones or don't. To get the behavior that I think that you are looking for I'd recommend specifying a zone on all of your tags/widgets.